Diloweralkl



n teds tes signors to Ciba Pharmaceutical Products, Inc., Summit, NJ.

No Drawing. Filed Llune 19, 1958, Ser. No. 743,004 Claims priority, application Switzerland July 17, 19 57 g i 'ClaimsJKCl. 260-309;): 5. The present, invention relates '7 to l-(lower .tertiary amino-lower alkyl)-benzimidaz-oles containing in the 2- position a naphthyl-methyl radical and in the 5-position a nitro group, as Welles to their salts. The invention relates more especially to benzimidazoles of the formula rN I C CHPRi in which A representsa lower :alkylene radical, more especially ethylene, and R 'representsa lower alkyleneimino group which may be interrupted by a hetero atom, such as a piperidino, pyrrolidino or morpholino'group, and particularly a di-lower alkyl-amino group, above all the diethylamino group, and in which formula R is an ct-naphthyl radical which is unsubstituted or substituted by a halogen atom or a lower alkyl or lower alkoxy group, and their salts.

The new compounds have. very good analgesic action and have better pharmacological properties than compan able benzylimidazoles, which 'makes them suitable as analgetics. Of special value, by virtue of its therapeutic properties, is the compound of the formula CH2 1H:

OzN

and its salts. I

The new benzimid-azoles are obtainable by as such known methods. According to one method, for example,

the lower tertiary amino-lower alkyl radical is introduced directly or by stages into the 1-position of a 5-nitro2- naphthyl-methyl benzimidazole. Thus, a 5-nitro-2- naphthyl-methyl-benzimidazole can be reacted with a reactive ester of an alcohol of the formula H0--A--R' in which A has the meaning defined above and R represents a tertiary amino group or a radical convertible into such a group, e.g. a hydroxyl group, and in the'resulting compound containing a radical convertible; into the tertiary amino group the said radical is so converted, thus, for example, a hydroxyl' group by chlorination and subsequent reaction with a secondary amine. Reactive esters are more especially those of strong inorganic or organic acids, such as those of hydrohalic acids or organic sulresents fonic acids, such as para-toluene sulfonic acid. The introduction. is preferably performed in the presenceof a condensing agent, more especially one that is'capable of forming metal salts with the S-nitro-2-naphthylmethylbenzimidazoles, such as the alkali and alkaline earth metals, for example sodium, lithium, calcium, their amides, hydrides, hydrocarbon compounds, alcoholates, oxides or hydroxides,'e.g. sodamide, sodium hydride, lithium butyl, potassium phenyl, lithium phenyl, potassium tertiary butylate, potassium tertiary amylate', sodium ethylate, sodium oxide or sodium hydroxide, or with the use of the pre-formed metal salts, of the benzimidazoles. This reaction generallyyields a mixture of S-Iiitro and 6-nitro derivatives which can be separated, for example,

by crystallizing their' bases or their-salts; 7

According to another process for the manufacture of the new compounds the benzimidazole ring substituted in the 2-position by a naphthyl-methyl group and in. the 5- position by a nitro group is formed by subjecting to ring closure a 2-(R"-NH)-5-nitraniline or a suitably N-substituted derivativethereof, R representingthe abovementioned group R--A-- or a radical convertible thereinto, eg, a halogeno-alkyl group. The radical convertible into the group R-A- is subsequently soconverted, in the case of the halogeno-alkyl group, for example, by reaction with a secondary amine. Thus, for example, a2- (tertiaryqaminoalkylamino)-5nitraniline can i be subjected to direct or stepwise ring closure witha'naphthylacetic acid or a reactive functional derivative thereof, more especially an esterwith an alcohol that isieasy' to split olf, or an iminoether. Furthermore, the final products of the invention can also be obtained by condensation with a naphthyl-acetaldehyde or with a functional derivative thereof, instead of with a naphthylacetic acid, the product thus formed then "being oxidized. Alternatively, the starting materials may be formed under the conditions employed in the afore-mentioned reactions; thus, for example, a Z-halogenoSmitro-naphthylthe. products of the invention canbe replaced by other acetyl aniline can be subjected to ring closure with .a

tertiary aminoalkylamineto produce the corresponding benzimidazole derivative.

The reactions of the present process are performed in I the presence or absence of diluents and/or condensing agents, if necessary at an elevated temperature, under atv mospheric or superatmospheric pressure. Substituents present in the'naphthyl-methyl radical of groups; thus, for example, a hydroxyl group may be converted into an etherified or esterified hydroxyl group, such 7 as a lower alkoxy group, or a nitro group can be converted into an amino group and the latter'converted into a lower alkoxy group or a halogen atom.

According to the reaction conditions employed the new compounds are obtained in the form of their free bases or of their salts. From the salts the free bases can be made in a such known manner. The latter, by being reacted with acids suitable for the formation of therapeutically useful salts, can be converted into salts, for example salts of the hydrohalic acids, sulfuric acid, nit-ric :acid, phosphoric acid, thiocyanic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, malic acid, methanesulfonic acid, ethanesulfonic acid, oxy r ethanesulfonic acid, ,benzenesulfonic or toluenesulfonic 'acid or of acids having therapeutic action.

The starting materials are known or can be made known methods.

process, and the remaining stage or stages are carried out.

Patented July 12, 1960 Thejnew compounds can be used as medicaments, for

example in the form of pharmaceutical preparations containing them or their salts in conjunction with a pharmaceutical organic or inorganic, solid or liquid excipient suitable for enteral, parenteral ortopical application. The excipient is made'from substances that do not react with the new compound, such for example, as water,'gelatine,

lactose, starches, magnesium stearate, talc, vegetable oils; benzyl alcohols, gums, polyalk'ylene glycols, white petro-.

7 Example 7.2 grams, of 2-(j8-diethylamino-ethylamino)-5-nitraniline hydrochloride in 90 cc. of glacial acetic acid'are added to m-naphthylacetic acid imino ether hydrochloride obtained from 12.5 grams of a-naphthyl-acetonitrile, 4.3 cc. of absolute ethanol in 50 cc. of chloroform by introducing dry hydrochloric acid gas at -l (3., allowing the whole to stand. for 16 hours at 25 C. and evaporation under diminished pressure. The mixture is then stirred for 20' hours. at 40-45 C. The reaction mixture is evaporated under reduced pressure, and the residue taken up in aqueous. hydrochloric acid; the acid solution is washed with. chloroform, rendered alkaline with ammonia solution, extracted with chloroform, and the chloroform ex- .tract'is washed with sodium carbonate s'olutionpdried with magnesium sulfate. and evaporated.

The resulting crude l-(fl-diethylamino-ethyl)-2-(unaphthylmethyl)-5nitro-benzin1idazole is converted into its hydrochloride meltin'giat.22'i-226 C.) by dissolution in ethanoland addition .of .oneequivalent of. ethanolic hydrochloric acid. f i A What is claimed is} 1. Benzimidazoles of the forniula wherein A stands for alower alkylenelradical, R for a thereof.

4. Therapeutically useful acid addition salts of the compounds of claim 1.

5. Therapeutically useful acid addition salts of 1-( 3- diethylaminoethyl) 2 a naphthyl methyl 5 nitro benzimidazole. I

, No references cited. 

3. A MEMBER OF THE GROUP CONSISTING OF 1-(B-DIETHYLAMINOETHYL)-5-NITRO-BENZIMIDAZOLE, CONTAINING IN 2-POSITION A MEMBER SELECTED FROM THE GROUP CONSISTING OF ANAPHTHYL-METHYL), (HALOGENO-A-NAPHTHYL)-METHYL, (LOWER ALKYL-A-NAPTHTHYL)-METHYL, AND (LOWER ALKOXY-A-NAPHTHYL)-METHYL AND THERAPEUTICALLY USEFUL ACID ADDITION SALTS THEREOF. 